Since a polymer electrolyte fuel cell (PEFC) has high power density, operates at low temperatures and hardly emits gas containing harmful substances, such a fuel cell has attracted attention as an energy source for transportation as an alternative to conventional internal-combustion engines.
A PEFC includes a polymer electrolyte membrane, on one face of which an anode is bonded and on the other face of which a cathode is bonded as electrodes. At the anode, hydrogen as fuel is supplied, and at the cathode, oxygen as oxidant is supplied, so that the fuel is oxidized to be protons at the anode and oxygen is reduced to water at the cathode for power generation. The anode and the cathode include electrode catalyst for fuel cell that is fine powder, in which a support made of carbon or the like supports catalyst particles made of noble metal such as Pt. In the electrodes for fuel cell serving as an anode and a cathode, such electrode catalyst for fuel cell is coated with ionomer that is made of solid polyelectrolyte.
For instance, an electrode for fuel cell has been proposed, including an electrode catalyst for fuel cell having a support made of the mixture of mesoporous carbon and carbon black, and catalyst particles supported on the support, the electrode catalyst for fuel cell being coated with ionomer (see Patent Document 1, for example).